Comfortable Ph changes??

[ehutchby]

What do our members think a comfortable Ph swing should be: from peak to low? For an SPS dominated tank.
Thoughts??
Mine peaks at 8.14 and then bottoms at 7.94 most days.
System parameters:
Total water volume: 120g
dkh 8.0, Ca 460, Mg 1320, phosphates are between 0 and .25, nitrates are undetectable.
My refugium light is kept on 24 hours a day.
I do not dose anything at night to buffer ph. but I'm thinking about it.
My tank is in my busines's office. Very good air circulation.
Currently I have several small SPS frags and polyps.
Many thanks for your thoughts..

[Percula9]

Your pH is well within normal limits for daily pH fluctuations. The phosphate level stated is a large difference between 0 and .25. You might add some phosban to the filter to lower PO4 levels. Buffers are not a good way to raise pH.

[Percula9]

Your pH is well within normal limits for daily pH fluctuations. The phosphate level stated is a large difference between 0 and .25. You might add some phosban to the filter to lower PO4 levels. Buffers are not a good way to raise pH.

[ehutchby]

Thanks for the response.. I have another question.
1. I don't know exactly what my phosphate level is because of my test kit. The color is between zero phosphates and the next level is .25. It sounds like I should get another test kit. Any recomendations??
2. I shouldn't have used the word buffer. I was thinking of dosing kalkwasser in the evening, on a timer, to "stabilize" the ph movement. Thoughts??

[tmz]

The swing in ph is less important in my opinion than the ph level. While your ph is fine, I personaly prefer ph beween 8.2 an 8.3. I've dosed limewater at night in the past with top off but now dose 24/7 since I am able to maintain more constant sg this way.

The phosphate can be a very serious issue for sps in particular. I couldn't deal with test kit readings either. A hannah colorimeter gives a digital readout and has helped in managing phosphate. It's a bit pricey initialy, but protecting the livestock and not overchanging gfo help offset the cost .

[Percula9]

Kalkwasser is a fine idea for pH help. Kalk might raise the alk a little so be watchful. I only worry about this, only for the fact your tank is in your office and out of view for a number of hours. I would hate for something to happen to it in the middle of the night like a kalk overdose. I think you should leave it alone. If the tank has a canopy, you can leave it off at night to improve gas exchange. As for PO4, if your not having algae problems I wouldn't worry about it to much. If you want to measure low levels then get a Hannah PO4 photometer.